Optical Virtual Private Network (OVPN) is a new service application emerging during transition of an optical network to Automatically Switched Optical Network (ASON). The OVPN provides users with a Virtual Private Network (VPN) service at a transport layer, and is also referred to as Layer 1 VPN (L1 VPN). An OVPN service, just like a conventional VPN service, enables users to build flexibly their own network topologies with a reduced communication cost within a public network, and allows a carrier to divide physical network resources so that end users are capable of viewing and managing their respective OVPNs generally and safely as in the case that they each own their own optical networks. Also, the OVPN enables a carrier to optimize a utilization ratio of bandwidth, and thus gains more business opportunities with fewer investments to thereby increase its revenue.
Various service modes, including a Basic Mode and an Enhanced Mode, for implementing the L1 VPN are described in the draft-ietf-l1vpn-framework by the IETF. The Enhanced Mode further includes an enhanced Overlay Mode, a Virtual Node mode, a Virtual Link mode, a Per VPN Peer mode, etc. Information exchanged between a Customer Edge (CE) and a Provider Edge (PE) and signaling routing approaches of the CE and the PE may vary from one mode to another.
Further, different modes correspond to different service scenarios. In scenarios of Multi-service Backbone, Carrier's carrier, etc., for example, dedicated resources are likely to be allocated to a user, and the user can monitor the performance of a dedicated circuit in a network of the carrier, here, the Virtual Link or Per VPN Peer mode may be used. In scenarios of Video Conference, Content Distribution, etc., link resources of a carrier are shared among respective VPNs, the Basic Mode may be used. Different users may have different demands for scenarios, and a carrier needs to be capable of supporting all scenarios required by the users. In other words, the carrier is required to be capable of supporting various service modes and hence supporting the different demands for scenarios.